Abstract To respond to the HIV epidemic and reduce health disparities in HIV incidence and outcomes, we propose a Prevention Research Center (PRC) at the University of California, San Francisco (UCSF) that facilitates significant and innovative health science research through partnerships with public health colleagues that ultimately improves public health. The HIV epidemic continues to be a major public health crisis in the U.S., with more than 1 million people living with HIV and more than 50,000 becoming newly infected every year. Given the progress in preventing and treating HIV, the Centers for Disease Control and Prevention (CDC) has identified HIV as a winnable battle, Healthy People 2020 has included HIV as a topic area, sexual health is part of the National Prevention Strategy, and United States has released the National HIV/AIDS Strategy. HIV has had a disproportionate impact on African Americans and transgender women, representing one of the largest health disparities in the U.S. While comprising just 13% of the total national population, African Americans account for 51% of all new HIV/AIDS diagnoses. The rate of new HIV infections is particularly profound for transgender women. About a quarter (22-28%) of transgender women are living with HIV, representing 34 times the odds of infection compared to the general population. More than half (about 56%) of African American transgender women are living with HIV. These data highlight the urgent need to focus research on eliminating HIV health disparities among African Americans in general and transgender women in particular. This application proposes to develop and implement authentic community engagement and a support implementation research project that focuses prevention HIV by linking, engaging and reengaging in care transgender women living with HIV. Our overall aims are to: 1. Maintain the multi-disciplinary UCSF PRC to catalyze high-quality applied health promotion and HIV prevention research; 2. Increase availability of evidence-based strategies, interventions, and implementation tools and facilitate innovative, high-impact, multidisciplinary HIV research and knowledge dissemination to address the HIV epidemic; 3. Develop and maximize the public health impact of optimally efficacious, culturally responsive, and implementable interventions, strategies, and prevention tools by moving them into policy and practice; 4. To conduct an applied public health prevention research project, using a community engaged approach, that addresses the significant health disparity in HIV among transgender women; and The PRC will include an administrative infrastructure, a community partnerships core, a dissemination and translation core, and an evaluation core. The work of the cores will be leveraged to reduce significant HIV- related health disparities and strengthen public health programs and practice.